In the aerospace industry, it is desirable to use composite parts made of reinforcing fibers embedded in a thermoplastic matrix. Parts made of reinforced thermoplastic composite materials may have smaller strength reductions at higher in-service temperatures than parts made of reinforced thermoset composite materials. Reinforced thermoplastic composite materials have higher toughness, including fracture toughness and Interlaminar Tension Strength (ILT), than reinforced thermoset composite materials.
Thermoplastics also offer certain advantages with respect to plies of reinforcing fibers pre-impregnated with resin. Unlike thermoset materials, thermoplastic materials do not have a shelf life and do not require refrigeration prior to processing. Thermoplastic materials also do not produce significant volatiles during consolidation.
However, current technology is not efficient at forming large integrally stiffened composite parts with continuous or long discontinuous (stretch broken) fiber reinforcement and thermoplastic resin. The scale of the equipment required to fabricate such parts can be impractical to operate and challenging to reconfigure.